Use of a Rubber Compound as a Material in the Insertion Area of Fuel Cells

ABSTRACT

The use of a rubber compound wherein the mechanical properties thereof are improved. In particular, the rubber compound has an increased elongation at rupture and/or increased tensile strength and/or increased tear strength and also a reduced compression set (DVR). The rubber compound includes a rubber having at least two functional groups which can be cross-linked by hydrosilylation, a cross-linking agent including hydrosiloxane or a hydrosiloxane derivative or a mixture of several hydrosiloxanes or derivatives, which include at least two SiH-groups per molecule in the centre, a hydrosilylation catalyst system, at least one filling material and a coagent which can be cross-linked by hydrosilylation, for use as a material in the insertion area of the fuel cells.

FIELD OF THE INVENTION

The invention relates to the use of a rubber compound as a material inthe area of application of fuel cells.

DESCRIPTION OF RELATED ART

European patent application EP 1 075 034 A1 describes the use ofpolyisobutylene or perfluoropolyether, crosslinked by hydrosilylation,as a sealing material in fuel cells.

U.S. Pat. No. 6,743,862 B2 discloses a crosslinkable rubber composition,preferably consisting of ethylene propylene diene monomer, with acompound having at least two SiH groups and optionally with a platinumcatalyst, and it describes its use as a sealing material.

European patent application EP 1 277 804 A1 discloses compositions madeof a vinyl polymer having at least one alkenyl group that can becrosslinked by hydrosilylation, of a compound with a componentcontaining hydrosilyl groups, of a hydrosilylation catalyst as well asof an aliphatic unsaturated compound having a molecular weight of notmore than 600 g/mol.

Terminal double bonds are decisive when a rubber is crosslinked byhydrosilylation. No undesired decomposition products that could migrateare created during the crosslinking. Consequently, these rubbercompositions are usually suitable for applications in which a cleanenvironment is especially important such as, for example, in fuel cells,in the medical sector or in the realm of food packaging.

Moreover, an improvement in the mechanical properties of the employedrubber types, especially those relating to tensile strength, elongationat break and/or compression set, is desirable in order to do justice tothe specific loads encountered in the cited areas of application.

So far, a reduction of the compression set has been achieved byincreasing the crosslinking density. This causes an increase in thehardness. However, the elongation at break often decreases at the sametime, which causes problems in many applications.

FIELD OF THE INVENTION

The invention is based on the objective of proposing the use of a rubbercompound with which an improvement of the mechanical properties ofrubbers is achieved, especially an increase in the elongation at breakand/or in the tensile strength and/or in the tear propagationresistance, along with a concurrent reduction in the compression set.

The envisaged objective is achieved by the features of claim 1.

For use in the area of application of fuel cells, according to theinvention, the rubber compound comprises a rubber (A) having at leasttwo functional groups that can be crosslinked by hydrosilylation, italso comprises, as the crosslinking agent (B), a hydrosiloxane orhydrosiloxane derivative or a mixture of several hydrosiloxanes orhydrosiloxane derivatives that, on average, have at least two SiH groupsper molecule, and it comprises a hydrosilylation catalyst system (C), atleast one filler (D) and a co-agent (E) that can be crosslinked byhydrosilylation.

The subordinate claims constitute advantageous refinements of thesubject matter of the invention.

In a preferred embodiment, the rubber compound additionally comprises atleast one additive (G).

In order to improve the mechanical properties of rubbers, especially inorder to increase the elongation at break, the tensile strength and/orthe tear propagation resistance, while concurrently reducing thecompression set, it is advantageous to use the following for the rubbercompound:

-   -   100 phr of rubber (A),    -   a quantity of the crosslinking agent (B), whereby the ratio of        SiH groups to functional groups that can be crosslinked by        hydrosilylation is 0.2 to 20, preferably 0.5 to 5, especially        preferably 0.8 to 1.2,    -   0.05 to 100,000 ppm, preferably 0.1 to 5000 ppm of the        hydrosilylation catalyst system (C),    -   5 to 800 phr of the at least one filler (D), preferably 10 to        200 phr for non-magnetic fillers, preferably 200 to 600 phr for        magnetic or magnetizable fillers, and    -   0.1 to 30 phr, preferably 1 to 10 phr, of the co-agent (E).

In a preferred embodiment, the rubber compound additionally contains 0.1to 20 phr of the at least one additive (F).

The abbreviation phr means parts per hundred of rubber; in other wordsit indicates the parts by weight per hundred parts by weight of rubber.

Preferred rubber compounds have proven to be those for which rubber (A)is selected from among

-   -   ethylene propylene diene monomer rubber (EPDM), whereby as the        diene, preferably a norbomene derivative having a vinyl group,        preferably 5-vinyl-2-norbornene, is used,    -   isobutylene isoprene divinyl benzene rubber (IIR terpolymer),        isobutylene isoprene rubber (IIR), butadiene rubber (BR),        styrene butadiene rubber (SBR), styrene isoprene rubber (SIR),        isoprene butadiene rubber (IBR), isoprene rubber (IR),        acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR),        acrylate rubber (ACM) or    -   partially hydrated rubber made of butadiene rubber (BR), styrene        butadiene rubber (SBR), isoprene butadiene rubber (IBR),        isoprene rubber (IR), acrylonitrile butadiene rubber (NBR),        polyisobutylene rubber (PIB) having two vinyl groups or rubber        functionalized, for example, with maleic acid anhydride or        maleic acid anhydride derivatives, or perfluoropolyether rubber        functionalized with vinyl groups.

An especially preferred rubber compound contains, as rubber (A),ethylene propylene diene monomer rubber (EPDM) having a vinyl group inthe diene or polyisobutylene (PIB) having two terminal vinyl groups.

Advantageously, the mean molecular weight of rubber (A) is between 5000and 100,000 g/mol, preferably between 5000 and 60,000 g/mol.

The following are preferably used as the crosslinking agent (B):

a compound containing SiH and having the Formula (I):

wherein R¹ stands for a saturated hydrocarbon group or for an aromatichydrocarbon group that is monovalent, that has 1 to 10 carbon atoms andthat is substituted or unsubstituted, whereby a stands for integersranging from 0 to 20 and b stands for integers ranging from 0 to 20, andR² stands for a bivalent organic group having 1 to 30 carbon atoms oroxygen atoms,

a compound containing SiH and having the Formula (II):

and/or

a compound containing SiH and having the Formula (III):

The crosslinking agent (B) is especially selected from amongpoly(dimethyl siloxane co-methyl hydrosiloxane), tris(dimethylsilyoxy)phenyl silane, bis(dimethyl silyloxy)diphenyl silane,polyphenyl(dimethyl hydrosiloxy)siloxane, methyl hydrosiloxane phenylmethyl siloxane copolymer, methyl hydrosiloxane alkyl methyl siloxanecopolymer, polyalkyl hydrosiloxane, methyl hydrosiloxane diphenylsiloxane alkyl methyl siloxane copolymer and/or polyphenyl methylsiloxane methyl hydrosiloxane.

Poly(dimethyl siloxane co-methyl hydrosiloxane) has proven to beespecially well-suited for building networks for difunctional vinylrubbers such as, for example, polyisobutylene having two terminal doublebonds.

Tris(dimethyl silyoxy)phenyl silane or bis(dimethyl silyloxy)diphenylsilane have proven to be especially suitable as crosslinking agents forrubbers having more than two functional groups in the molecule that canbe crosslinked by hydrosilylation such as, for example, for ethylenepropylene diene monomer rubber (EPDM) with 5-vinyl-2-norbomene as thediene.

The hydrosilylation catalyst system (C) is preferably selected fromamong platinum(0)-1,3-divinyl-1,1,3,3,-tetramethyl disiloxane complex,hexachloroplatinic acid, dichloro(1,5-cyclooctadiene)platinum(II),dichloro(dicyclopentadienyl)-platinum(II), tetrakis(triphenylphosphine)platinum(0), chloro(1,5-cyclooctadiene)rhodium(I)dimer,chlorotris(triphenyl phosphine)rhodium(I) and/ordichloro(1,5-cyclooctadiene)palladium(II), optionally in combinationwith a kinetics regulator selected from among dialkyl maleate,especially dimethyl maleate, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclosiloxane, 2-methyl-3-butin-2-ol and/or l-ethinyl cyclohexanol.

The at least one filler (D) is advantageously selected from furnace,flame and/or channel black, silicic acid, metal oxide, metal hydroxide,carbonate, silicate, surface-modified or hydrophobized, precipitatedand/or pyrogenic silicic acid, surface-modified metal oxide,surface-modified metal hydroxide, surface-modified carbonate, such aschalk or dolomite, surface-modified silicate, such as kaolin, calcinatedkaolin, talcum, quartz powder, siliceous earth, layer silicate, glassbeads, fibers and/or organic fillers such as, for example, wood flourand/or cellulose.

Hydrophobized or hydrophobic silicic acids can be incorporatedespecially well into non-polar rubbers and translate into a lesserincrease in viscosity as well as better mechanical values in comparisonto unmodified silicic acids.

The co-agent (E) is advantageously selected from among2,4,6-tris(allyloxy)-1,3,5-triazine (TAC), triallyl isocyanurate (TAIC),1,2-polybutadiene, 1,2-polybutadiene derivatives, diacrylates,triacrylates, especially trimethyl propane triacrylate, dimethacrylatesand/or trimethacrylates, especially trimethylol propane trimethacrylate(TRIM), triallyl phosphonic acid esters and/or butadiene styrenecopolymers having at least two functional groups that bond to rubber (A)by hydrosilylation.

The following are used as additive (F):

-   -   anti-ageing agents, for example, UV absorbers, UV screeners,        hydroxybenzophenone derivatives, benzotriazo derivatives or        triazine derivatives,    -   antioxidants, for example, hindered phenols, lactones or        phosphites,    -   ozone protection agents, for example, paraffinic waxes,    -   flame retardants,    -   hydrolysis protection agents, such as carboduimide derivatives,    -   bonding agents such as silanes having functional groups that        bond to the rubber matrix by hydrosilylation, for example,        polymers modified with vinyl trimethoxy silane, with vinyl        triethoxy silane, with rubbers functionalized with maleic acid        derivatives, for example, maleic acid anhydride,    -   mold release agents or agents for reducing the tackiness of        components such as, for instance, waxes, fatty acid salts,        polysiloxanes, polysiloxanes having functional groups that bond        to the rubber matrix by hydrosilylation and/or    -   dyes and/or pigments,    -   plasticizers and/or    -   processing auxiliaries.

The method for the production of such a rubber compound does notgenerate any by-products during the crosslinking that have to be removedin a laborious procedure. No decomposition products are released thatcan migrate and that can be problematic for applications in the realm offuel cells. Moreover, the crosslinking with a relatively small amount ofhydrosilylation catalyst system takes place more quickly than withconventional materials.

In order to produce the rubber compounds described, first of all, rubber(A), the at least one filler (D) and the co-agent (E) and/or the atleast one additive (F) are mixed, the crosslinking agent (B) and thehydrosilylation catalyst system (C) are added as a one-component systemor as a two-component system and all of the components are mixed.

In the case of a one-component system, the crosslinking agent (B) andthe hydrosilylation catalyst system (C) are added to the above-mentionedother components in a system or in a container. In contrast, with thetwo-component system, the crosslinking agent (B) and the hydrosilylationcatalyst system (C) are mixed separately from each other, that is tosay, in two systems or containers, each at first with part of a mixtureof the other components, until they are homogeneously blended, beforethe two systems, that is to say, the mixture with the crosslinking agent(B) and the mixture with the hydrosilylation catalyst system (C), arecombined with each other, and all of the components are mixed together.The two-component system has the advantage that the two mixtures, inwhich the crosslinking agent (B) and the hydrosilylation catalyst system(C) are separate from each other, can be stored for a longer period oftime than a mixture that contains the crosslinking agent (B) as well asthe hydrosilylation catalyst system (C).

Subsequently, the product is processed by an injection-molding or(liquid) injection-molding method ((L)IM), by a compression-moldingmethod (CM), by a transfer-molding method (TM) or by a method derivedfrom any of these, by a printing process such as, for example,silkscreen printing, by bead application, dip-molding or spraying.

The above-mentioned rubber compounds are used as material in the area ofapplication of fuel cells.

Preferably, the rubber compounds are used as a material for seals suchas loose or integrated seals, for instance, O-rings or chevron-typesealing rings, adhesive seals, soft-metal seals or impregnations, forcoatings, membranes or adhesive compounds for hoses, valves, pumps,filters, humidifiers, reformers, storage tanks, vibration absorbers, forcoatings of fabrics and/or non-wovens.

An especially advantageous embodiment of the rubber compounds is theiruse as seals for fuel cell stacks in the form of, for example, profiledor unprofiled seals. Preferably, the rubber compounds according to theinvention are also used on a bipolar plate, a membrane, a gas diffusionlayer or in profiled or unprofiled seals integrated into amembrane-electrode unit.

WAYS TO EXECUTE THE INVENTION

The subject matter of the invention will be explained below withreference to a number of examples.

A rubber (A), a filler (D) and a co-agent (E) are mixed in a mnixer,namely, a SpeedMixer DAC 400 FVZ made by the Hausschild & Co. KGcompany, at temperatures between 30° C. and 60° C. [86° F. and 140° F.]until the components are homogeneously mixed. Subsequently, acrosslinking agent (B) and a hydrosilylation catalyst system (C) areadded, and the mixture is further mixed until the components arehomogeneously blended.

This mixture is then compression-molded under vulcanization conditionsat 150° C. [302° F.], for example, in a press, to form 2 mm-thickplates.

Ethylene propylene 5-vinyl-2-norbornene rubber made by the MitsuiChemicals company and having a norbomene content of 5.3% by weight and amean molecular weight of 31,000 g/mol (Mitsui EPDM) or polyisobutylene(PE:B) having two vinyl groups made by the Kaneka company and having amean molecular weight of 16,000 g/mol (EPION-PIB (EP 400)) is used asrubber (A).

Tris(dimethylsilyloxy)phenyl silane made by the Shin Etsu company isused as the hydrosilylation crosslinking agent (B) for the Mitsui EPDM.This crosslinking agent is especially well-suited for rubbers that havemore than two vinyl groups in the molecule.

2,5-Dimethyl-2,5-di(tert-butyl peroxy)hexane made by Arkema Inc.(Luperox 101 XL-45) is used as the peroxide crosslinking agent for theMitsui EPDM.

Poly(dimethyl siloxane co-methyl hydrosiloxane) made by the Kanekacompany (CR 300) is used as the hydrosilylation crosslinking agent (B)for the polyisobutylene terminal-functionalized with two vinyl groups(EPION-PIB (EP 400)). CR 300 has more than 3 SiH groups per molecule andis thus especially well-suited for building networks for difunctionalvinyl rubbers such as polyisobutylene having two vinyl groups.

A so-called Karstedt catalyst is used as the hydrosilylation catalystsystem (C), namely, platinum(0)-1,3-divinyl-1,1,3,3,-tetramethyldisiloxane complex, that has been dissolved in a 5% concentration inxylene and that is used in combination with dimethyl maleate as akinetics regulator.

Hydrophobized pyrogenic silicic acid made by the Degussa company(Aerosil R8200) is used as the filler (D). Hydrophobized or hydrophobicsilicic acids can be incorporated especially well into non-polar rubbersand cause a lesser increase in viscosity as well as a better compressionset in comparison to silicic acids that have not been surface-modified.

Triallyl isocyanurate (TAIC) made by the Nordmann, Rassmann GmbH companyor else 1,2-polybutadiene (Nisso PB B-3000) made by Nippon Soda Co.,Ltd. or trimethylol propane triacrylate (Saret 519) made by the Sartomercompany is used as the co-agent (E) that can be crosslinked byhydrosilylation.

The invention can be better understood with reference to the followingexamples from Tables I to IV.

The rubber compounds with and without a co-agent undergo the followingtests:

hardness [Shore A] according to DIN 53505, tensile strength [MPa], DIN53504-S2, modulus 100% [MPa] and elongation at break [%] according tocompression set [%] according to DIN ISO 815, (25% deformation, 24 hrsor 70 hrs at 120° C. [248° F.] or 150° C. [302° F.] in air) and tearpropagation resistance [N/mm] according to DIN 53507-A.

Tables Ia and Ib give examples, whereby ethylene propylene5-vinyl-2-norbomene rubber made by the Mitsui Chemicals company is usedas rubber (A).

Tris(dimethyl silyoxy)phenyl silane is used as the hydrosilylationcrosslinking agent (B) for the Mitsui EPDM in a dose that is adapted tothe double bonds supplied by the co-agent (E).

TABLE Ia Hydrosilylation Hydrosilylation Peroxide Peroxide compound withHydrosilylation compound compound compound co-agent compound withwithout co- with co- without co- Example Nisso-PB co-agent TAIC agentagent TAIC agent Rubber (A): 100 100 100 100 100 Mitsui EPDM [phr]Hydrosilylation 5 6 4 crosslinking agent (B): tris(dimethylsilyoxy)phenyl silane [phr] Peroxide 4 4 crosslinking agent [phr]Catalyst system (C): 56/36 56/36 56/36 ≈450 ppm catalyst/regulator [μl]Filler (D): 20 20 20 20 20 Aerosil R8200 [phr] Co-agent (E): [phr] 1 2 2TAIC Nisso-PB B-3000 Hardness [Shore A] 40 46 38 52 46 Tensile strength1.6 1.5 1.4 2 1.5 [MPa] Modulus 100% [MPa] 0.9 1.3 1 1.3 Elongation atbreak 153 115 129 83 109 [%] Tear propagation 0.9 0.6 0.7 resistance[N/mm] Compression set at 20 10 25 9 11 120° C. [248° F.], 24 hrs [%]

As is known, a number of secondary reactions can occur during thecrosslinking of EPDM with peroxides, some of which can be suppressed bythe use of co-agents.

Moreover, by increasing the crosslinking density, the addition of aco-agent such as, for instance, 1,2-polybutadiene (Nisso PB B-3000) ortriallyl isocyanurate (TAIC) during peroxide crosslinking of Mitsui EPDMtranslates into an increase in the hardness and a decrease in thecompression set, but also an undesired decrease in the elongation atbreak.

In the case of Mitsui EPDM crosslinked by hydrosilylation, the increasein the crosslinking density due to the addition of the co-agent1,2-polybutadiene (Nisso PB B-3000) or of triallyl isocyanurate (TAIC)translates into an increase in the hardness and an increase in thetensile strength. The addition of a co-agent (E) also brings about amarked reduction in a permanent deformation of the rubber under load,that is to say, a decrease in the compression set value.

Surprisingly, the elongation at break increases with Mitsui EPDMcrosslinked by hydrosilylation in contrast to Mitsui EPDM crosslinked byperoxide, especially after the addition of 1,2-polybutadiene (Nisso PBB-3000) as the co-agent. This positive effect opens up improvedapplication possibilities to use this rubber compound in numerous areasof application.

In particular, the elongation at break is also increased as a result ofthe addition of diacrylates, for example, of 1,6-hexane dioldiacrylate(SR 238) made by the Sartomer company, as is shown in Table Ib.

TABLE Ib Hydrosilylation compound with Hydrosilylation co-agent compoundwithout Example (SR 238) co-agent Rubber (A): Mitsui EPDM [phr] 100 100Hydrosilylation crosslinking agent (B): CR 300 [phr] 4 4 Catalyst system(C): catalyst/regulator [phr]/[μl] 0.2/35 0.2/35 dimethyl maleate Filler(D): Aerosil R8200 [phr] 20 20 Co-agent (E): [phr] 1,6-hexanedioldiacrylate (SR 238) 1 Hardness [Shore A] 32 38 Tensile strength[MPa] 1.7 1.4 Modulus 100% 0.9 1 Elongation at break [%] 162 129Compression set at 120° C. 18 25 [248° F.], 24 hrs [%] Compression setat 120° C. 26 40 [248° F.], 70 hrs [%]

Table IIa shows examples, whereby polyisobutylene (PIB) having two vinylgroups made by the Kaneka company (EPION-PIB (EP 400)) is used as rubber(A).

Poly(dimethyl siloxane co-methyl hydrosiloxane) made by the Kanekacompany (CR 300) is used as the hydrosilylation crosslinking agent (B)for the polyisobutylene terminal-functionalized with two vinyl groups(EPION-PIB (EP 400)) in a dose that is adapted to the double bondssupplied by the co-agent (E).

TABLE IIa Hydrosilylation Hydrosilylation compound with compound withHydrosilylation co-agent co-agent compound Example Saret 519 Saret 519without co-agent Rubber (A): EPION-PIB (EP 400) [phr] 100 100 100Crosslinking agent (B): CR 300 [phr] 6.5 8 4 Catalyst system (C): ≈450ppm HS-KA 56/36 56/36 56/36 catalyst/regulator [μl] Filler (D): AerosilR8200 [phr] 20 20 20 Co-agent (E): Saret 519 [phr] 2 2 Hardness [ShoreA] 29 35 35 Tensile strength [MPa] 2.7 2.9 2.6 Modulus 100% [MPa] 0.60.7 0.7 Elongation at break [%] 328 299 261 Tear propagation resistance[N/mm] 2.5 2.3 2 Compression set at 120° C. [248° F.], 24 hrs [%] 31 2833

In the case of polyisobutylene having two vinyl groups (EPION-PIB (EP400)) crosslinked by hydrosilylation, the addition of trimethylolpropane triacrylate (Saret 519) as the co-agent (E) translates into anincrease in the tensile strength and a decrease in the compression setat 120° C. [248° F.].

Surprisingly, when the co-agent (E) is added, the elongation at breakincreases in the case of polyisobutylene having two vinyl groups(EPION-PIB (EP 400)) crosslinked by hydrosilylation. The tearpropagation resistance also increases when the co-agent (E) is added.

TABLE IIb Hydrosilylation Hydrosilylation compound with compound withHydrosilylation co-agent co-agent compound Example Nisso PB B-3000 TAICwithout co-agent Rubber (A): EPION-PIB (EP 400) [phr] 100 100 100Crosslinking agent (B): CR 300 [phr] 8.5 8.5 4 Catalyst system (C):catalyst/regulator [phr]/[μl] 0.2/35 0.2/35 0.2/35 dimethyl maleateFiller (D): Aerosil R8200 [phr] 20 20 20 Co-agent (E): [phr] Nisso-PBB-3000 1 TAIC 1 Hardness [Shore A] 32 37 35 Tensile strength [MPa] 3.43.2 2.6 Modulus 100% [MPa] 0.6 0.8 0.7 Elongation at break [%] 359 270261 Compression set at 120° C. [248° F.], 24 hrs [%] 55 30 33Compression set at 120° C. [248° F.], 70 hrs [%] 70 35

Table IIb shows the effect of the addition of the co-agent1,2-polybutadiene (Nisso PB B-3000) or of triallyl isocyanurate (TAIC)on various mechanical properties.

With the addition of these co-agents (E) as well, the hydrosilylationcompound with polyisobutylene displays increased tensile strength valuesand, exactly like with the addition of trimethylol propane triacrylate(Saret 519), surprisingly improved elongation at break properties.

In particular, the compression set values after 24 hours at 120° C.[248° F.] in air can also be lowered as a result of the addition ofacrylate and triallyl isocyanurate (TAIC).

TABLE III Hydrosilylation Hydrosilylation compound with compound withHydrosilylation co-agent co-agent compound Example TAIC Nisso PB B-3000without co-agent Rubber (A): Perbunan NBR [phr] 100 100 100 Crosslinkingagent (B): CR 300 [phr] 10 10 10 Catalyst system (C): catalyst/regulator[phr]/[μl] 0.2/0.04 0.2/0.04 0.2/0.04 Filler (D): Aerosil R8200 [phr] 6060 60 Co-agent (E) [phr]: TAIC 2.5 Nisso PB B-3000 2.5 Hardness [ShoreA] 76 78 75 Tensile strength [MPa] 9.2 8.7 6.2 Modulus 100% [MPa] 4.47.7 2.9 Modulus 200% [MPa] 8.4 5.2 Elongation at break [%] 228 116 236Tear propagation resistance [N/mm] 12.2 11.7 10 Compression set at 120°C. [248° F.], 24 hrs [%] 20 21 18

Acrylonitrile butadiene rubber (NBR) made by the Lanxess company(Perbunan 2845 F) is used in the examples compiled in Table III.

In addition to rubber (A) without a co-agent and with the co-agent (E),the data of Table III turns to the example of the use of the co-agenttriallyl isocyanurate (TAIC) or 1,2-polybutadiene (Nisso PB B-3000) toshow how the mechanical properties are influenced by the addition of aco-agent (E) that can be crosslinked by hydrosilylation.

The hardness values are increased as a result of the addition of aco-agent (E) and so are the tensile strength values. The same applies tothe tear propagation resistance when the co-agent (E) is added.

In this context, the hydrosilylation compounds with the co-agenttriallyl isocyanurate (TAIC) display even somewhat higher tensilestrength, elongation at break and tear propagation resistance values aswell as a somewhat lower compression set in comparison to those with theco-agent 1,2-polybutadiene (Nisso PB B-3000).

Moreover, the measured data compiled in Table IV for the comparativeexamples with hydrosilylation compounds with acrylate rubber (ACM OR 100A) made by the Kaneka company as rubber (A) without a co-agent and withthe co-agent (E), for example, using the co-agent triallyl isocyanurate(TAIC), triacrylate (Saret 519) or 1,2-polybutadiene (Nisso PB B-3000),shows how the mechanical properties are influenced by the addition of aco-agent (E) that can be crosslinked by hydrosilylation.

TABLE IV with co- with co- with co- with co- with co- agent Exampleagent agent agent agent Nisso PB without hydrosilylation compound TAICTAIC Saret 519 Saret 519 B-3000 co-agent Rubber (A): 100 100 100 100 100100 ACM [phr] Crosslinking agent (B): 15.5 17 12 14 12 6 CR 500 [phr]Catalyst system (C): 47/32 47/32 47/32 47/32 47/32 47/32Pt-VTSc/dimethyl maleate catalyst/regulator [μl]/[μl] Filler (D): 30 3030 30 30 30 Aerosil R8200 [phr] Co-agent (E): [phr] 2 2 2 2 2 TAIC Saret519 Nisso-PB B-3000 Additive (F): [phr] 1 1 1 1 1 1 anti-ageing agentAnox 20 (BASF) Density [g/cm³] 1.23 1.23 1.24 1.23 1.24 1.21 DIN EN ISO1183 Hardness [Shore A] 33 36 25 30 27 22 Tensile strength [MPa] 3.4 4.13 3.3 3.1 2.4 Elongation at break [%] 167 164 240 215 220 224Compression set at 150° C. 23 9 36 19 50 41 [302° F.], 70 hrs [%]

The hardness values here are increased as a result of the addition of aco-agent (E) and so are the tensile strength values. Noteworthy here isthe improvement of the compression set after 70 hours at 150° C. [302°F.] as a result of the addition of a co-agent from the group ofacrylates, as shown with the triacrylate (Saret 519), and especially asa result of the addition of the co-agent triallyl isocyanurate (TAIC).

The examples compiled in the tables show that the rubber compounds thatcontain ethylene propylene diene monomer rubber (EDPM), polyisobutylene(PIB), acrylonitrile butadiene rubber (NBR) or acrylate rubber (ACM) asrubber (A), and that contain triallyl isocyanurate (TAIC),1,2-polybutadiene, triacrylates (Saret 519) or diacrylates such as, forexample, 1,6-hexane dioldiacrylate (SR 238) as co-agent (E) haveespecially advantageous mechanical properties.

Hydrosilylation compounds containing 1,2-polybutadiene or ether groupsas co-agents tend towards slightly worse mechanical properties,especially in terms of thermal ageing, which is evident from thecompression set values at 120° C. [248° F.] and higher temperatures.

1-12. (canceled)
 13. A fuel cell material for use in an application areaof a fuel cell comprising: a rubber compound, the rubber compoundcomprising: a rubber having at least two functional groups that can becrosslinked by hydrosilylation; a crosslinking agent comprising ahydrosiloxane or hydrosiloxane derivative or a mixture of severalhydrosiloxanes or hydrosiloxane derivatives that, on average, have atleast two SiH groups per molecule; a hydrosilylation catalyst system, atleast one filler and a co-agent that can be crosslinked byhydrosilylation.
 14. The fuel cell material as recited in claim 13,wherein the rubber compound further comprises at least one additive. 15.The fuel cell material as recited in claim 13, wherein the rubbercompound contains: 100 phr of rubber; a quantity of the crosslinkingagent, wherein the ratio of SiH groups to functional groups that can becrosslinked by hydrosilylation is 0.2 to 20; 0.05 to 100,000 ppm of thehydrosilylation catalyst system; 5 to 800 phr of the at least onefiller; and 0.5 to 30 phr of the co-agent.
 16. The fuel cell material asrecited in claim 15, wherein the ratio of the SiH groups to functionalgroups that can be crosslinked by hydrosilylation is 0.5-5.
 17. The fuelcell material as recited in claim 16, wherein the ratio of the SiHgroups to functional groups that can be crosslinked by hydrosilylationis 0.8-1.2.
 18. The fuel cell material as recited in claim 15, whereinthe amount of the hydrosilylation catalyst system is 0.1 to 5,000 ppm.19. The fuel cell material as recited in claim 15, wherein the amount offiller is 10 to 200 phr for nonmagnetic fillers or 200 to 600 phr formagnetic or magnetizable fillers.
 20. The fuel cell material as recitedin claim 15, wherein the amount of coagent is 1 to 10 phr.
 21. The fuelcell material as recited in claim 14, wherein the rubber compoundcontains 0.1 to 20 phr of the at least one additive.
 22. The fuel cellmaterial as recited in claim 13, wherein the rubber is selected fromamong ethylene propylene diene monomer rubber (EPDM); isobutyleneisoprene divinyl benzene rubber (IIR terpolymer), isobutylene isoprenerubber (IIR), butadiene rubber (BR), styrene butadiene rubber (SBR),styrene isoprene rubber (SIR), isoprene butadiene rubber (IBR), isoprenerubber (IR), acrylonitrile butadiene rubber (NBR), chloroprene rubber(CR), acrylate rubber (ACM); or partially hydrated rubber made ofbutadiene rubber (BR), styrene butadiene rubber (SBR), isoprenebutadiene rubber (IBR), isoprene rubber (IR), acrylonitrile butadienerubber (NBR), polyisobutylene rubber (PIB) having two vinyl groups orrubber functionalized.
 23. The fuel cell material as recited in claim22, wherein the ethylene-propylene-diene monomer rubber is a norbomenederivative having a vinyl group.
 24. The fuel cell material as recitedin claim 23, wherein the norbornene derivative having a vinyl group is5-vinyl-2-norbornene.
 25. The fuel cell material as recited in claim 22,wherein the rubber is functionalized with maleic anhydride or maleicacid anhydride derivatives or is perfluoropolyether rubberfunctionalized with vinyl groups.
 26. The fuel cell material as recitedin claim 13, wherein the mean molecular weight of rubber is between 5000and 100,000 g/mol
 27. The fuel cell material as recited in claim 26,wherein the mean molecular weight of rubber is between 5000 and 60,000g/mol.
 28. The fuel cell material as recited in claim 13, wherein thecrosslinking agent is selected from among a compound containing SiH andhaving the Formula (I):

wherein R¹ stands for a saturated hydrocarbon group or for an aromatichydrocarbon group that is monovalent, that has 1 to 10 carbon atoms andthat is substituted or unsubstituted, wherein a stands for integersranging from 0 to 20 and b stands for integers ranging from 0 to 20, andR² stands for a bivalent organic group having 1 to 30 carbon atoms oroxygen atoms, a compound containing SiH and having the Formula (II):

a compound containing SiH and having the Formula (III):


29. The fuel cell material as recited in claim 28, wherein thecrosslinking agent includes poly(dimethyl siloxane co-methylhydrosiloxane), tris(dimethyl silyoxy)phenyl silane, bis(dimethylsilyloxy)diphenyl silane, polyphenyl(dimethyl hydrosiloxy)siloxane,methyl hydrosiloxane phenyl methyl siloxane copolymer, methylhydrosiloxane alkyl methyl siloxane copolymer, polyalkyl hydrosiloxane,methyl hydrosiloxane diphenyl siloxane alkyl methyl siloxane copolymerand/or polyphenyl methyl siloxane methyl hydrosiloxane.
 30. The fuelcell material as recited in claim 13, wherein the hydrosilylationcatalyst system is selected from among hexachloroplatinic acid,platinum(0)-1,3-divinyl-1,1,3,3,-tetramethyl disiloxane complex,dichloro(1,5-cyclooctadiene)platinum(II),dichloro(dicyclopentadienyl)-platinum(II), tetrakis(triphenylphosphine)platinum(0), chloro( 1,5-cyclooctadiene)rhodium(I)dimer,chlorotris(triphenyl phosphine)rhodium(I) and/ordichloro(1,5-cyclooctadiene)palladium(II).
 31. The fuel cell material asrecited in claim 30, further comprising a kinetic regulator selectedfrom among dialkyl maleate, in particular dimethyl maleate,1,3,5,7-tetramethyl-1,3,5,7-tetravinyl cyclosiloxane,2-methyl-3-butyn-2-ol and/or 1-ethynylcyclohexanol.
 32. The fuel cellmaterial as recited in claim 13, wherein the at least one filler isselected from carbon black, graphite, silicic acid, silicate, metaloxide, metal hydroxide, carbonate, glass beads, fibers and/or organicfillers.
 33. The fuel cell material as recited in claim 13, wherein theco-agent is selected from among 2,4,6-tris(allyloxy)-1,3,5-triazine(TAC), triallyl isocyanurate (TAIC), 1,2-polybutadiene,1,2-polybutadiene derivatives, diacrylates, triacrylates.
 34. The fuelcell material as recited in claim 33, wherein the triacrylate includestrimethylpropane triacrylate, dimethacrylates and/or trimethacrylates,especially trimethylol propane trimethacrylate (TRIM), triallylphosphonic acid esters and/or butadiene-styrene copolymers having atleast two functional groups that bond to rubber by hydrosilylation. 35.The fuel cell material as recited in claim 14, wherein the at least oneadditive is selected from among anti-ageing agents, antioxidants, ozoneprotection agents, flame retardants, hydrolysis protection agents,bonding agents, mold release agents or agents for reducing the tackinessof components, dyes and/or pigments, plasticizers and/or processingauxiliaries.
 36. The fuel cell material as recited in claim 13, whereinthe area of application is as a material for seals or impregnations,coatings, membranes or adhesive compounds for hoses, valves, pumps,filters, humidifiers, reformers, storage tanks, vibration absorbers, forcoatings of fabrics and/or non-wovens.
 37. A method for manufacturing afuel cell comprising: placing the fuel cell material as recited in claim13 in the application area.